Device for presenting cutting edges for cutting ability indexing



May 3, 1960 E, J. CASSELMAN 2,934,994

I DEVICE FOR PRESENTING CUTTING EDGES FOR CUTTING ABILITY INDEXING Fild May 31, 1957 2 Sheets-Sheet 1 INVENTOR.

[Iii/96E .Z cwss znfl/r y 1960 E. J. CASSELMAN 2,934,994

DEVICE FOR PRESENTING CUTTING EDGES FOR CUTTING ABILITY INDEXING Filed May 31, 1957 2 Sheets-Sheet 2 nk II WWW United DEVICE FOR PRESENTING CUTTING EDGES FOR CUTTING ABILITY INDEXING Application May 31, 1957, Serial No. 663,862

4 Claims. (Cl. 88-14) The present invention relates generally to a light scanning apparatus for determining the cutting ability of a cutting instrument such as a knife or razor blade and more particularly to that part of such apparatus which presents its edge always in a predetermined spatial relation to the light scanning .means.

One of the problems presented in cutting edge evaluation by light scanning means arises from the fact that cutting instruments vary widely from each other in many respects, one of which is that the cutting edge to be indexed is other than straight. For example, some cutting edges are continuous but at different spatial levels, such as curved cutting edges. It has been difiicult to index such cutting edges because the light scanning mechanism is stationary and directs light beams on a single spatial level so that the ordinary methods of indexing straight cutting edges cannot be used with cutting edges which are on different spatial-levels.

One of the objects of this invention is to standardize that part of the apparatus which presents a cutting edge to the light scanning means so that the edge to be scanned will always be in that predetermined spatial relationship thereto which the apparatus contemplates and in fact requires and that it servethis purpose accurately and with preciseness regardless of the type cutting instrument .whose edge it is desired to evaluate.

Another object of the invention is that the cuttingedge presenting device be such that the cutting edge portion to bescanned of any and all of said different types of cutting instruments be always presented to the light scanning means at the same predetermined level and spatial relation to the scanning means.

A further object of the invention is that the device which presents a cutting edge to a scanning light beam be such that any particular section thereof may be scanned.

A still further object of the invention is the provision of an arrangement which permits any section of a curved cutting edge to be scanned without adjustment of the light-scanning means.

A still further object of the invention is the provision of an arrangement which prevents or shields reflection of light from all parts except the blade edge.

Other and further objects of the present invention will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

For convenience of disclosure, the invention will be exemplified by reference to the blade of a surgeons knife where the cutting edge is curved, it being understood however that the present invention is intended to operate in the same or a similar manner for cutting edges which are otherwise conformed.

Av preferred embodiment of the invention has been chosen for purposes of illustration and description and tes Patent: C

is shown in the accompanying drawings, forming a part of the specification, wherein:

Fig. l is an enlarged transverse section through the cutting edge of the blade of a surgeons knife which is the form of knife with which my invention isadapted to be utilized.

Fig. 1A is a longitudinal transverse section of a corner of said blade to a smaller scale than Fig. 1.

Fig. 2 is a side elevational view of the knife-presenting apparatus showing the blade in position to have any section of its cutting edge scanned by a light beam;

Fig. 3 is a view similar to Fig. 2 showing the blade in position to have a particular section of its curved edge scanned;

Fig. 4 is a top view of the apparatus shown in Fig. 2;

Fig. 5 is a rear end view of the knife-presenting apparatus;

Fig. 6 is a sectional view taken along line 6--6 of Fig. 2;

Fig. 7 is, a sectional view taken along line 77 of Fig. 2;

Fig. 8 is a sectional view taken along line 88 of Fig. 2; and

Fig. 9 is a sectional view taken along line 9-9 of Fig. 2.

The device shown in the drawings and now to be described, while structurally devised for scanning the curved cutting edge of the blade used for surgeons knives can by changes in details of the construction serve also for accommodating other blades and to this extent reference to a cutting edge will be understood as generic unless otherwise expressly stated in the claims.

Fig. 1A shows a blade for a surgeons knife having a curved edge 3. It will be noted that the curved edge 3 has each point on the edge at a difierent spatial level. The curved edge 3 is a simple curve with a single radius having a single center of curvature. Said curved edge is tangent to the straight cutting edge portion of the blade. It also will be observed that the cutting edge portion of said curved edge 3 is on the outside of the curve.

Fig. l of the drawings shows in a greatly enlarged transverse cross-sectional view a typical cutting edge of any cutting tool, such edge, where ideal, is defined by symmetrical converging faces x and y joined at apex p to provide symmetrical halves on opposite sides of the plane centrally through the apex. A scanning light beam A is shown as directed upon one of said halves to scan a limited length thereof and reflected at B to a light responsive device (not shown) which analyzes and indexes the reflected beam. The preferred practice uses a plurality of such beams spaced apart lengthwise of the blade to give the resultant of plural indexing along the blade edge.

A significant fact to be referred to further is that the light scanning beam or beams are fixed in the direction of their paths and that there are light values at the point where they strike the edge being scanned that also remain constant and that any section of the blade edge to be scanned will be presented in the same predetermined spatial relation to the scanning means.

he problem to which the illustrative embodiment directs itself is that each section of the blade edge be presented to the scanning means as shown in Fig. 1 even where its cutting edge is curved as illustrated and that its cutting edge will always be presented at the same spatial relationship to the scanning beam or beams precisely asis the blade edge in the showing of Fig. 1.

Referring more particularly to Fig. 2, the blade holder 4 is comprised of an elongated hollow handle member 5 having an upstanding standard 6 at its front end. Pivotally mounted on the upstanding standard 6 on the pin 7 is a rotating blade receiver 8 which is adapted to receive the blade 1 (see Fig. 3). The blade receiver 8 is provided with a pair of clamping members 9 and 10 be- 9 and 10. a

In order to correctly locate the blade 1 between the clamping members 9 and 1%), a locating member 12 is slidably .mounted on the blade receiver 8. The locating member 12 is mounted on blade receiver 8 by means of set screw 13 passing through vertical slot 14 in locating member 12 so that the locating member 12 can be moved vertically (Fig. 8) as will be more fully described hereinafter.

The pivot 7 is located a distance from. all points on. the curved cutting edge 3 of the blade 1 equal to the dis tance to the-straight cutting edge 2 so that when the blade receiver 8 is rotated (Fig. 3) each portion of the curved cutting edge 3 of the blade 1 will occupy the same elevational plane as the straight cutting edge 2,. In

other words, the blade receiver 8 rotates about an axis 7 which is also the center of the curved cutting edge 3 of the blade 1.

In order to rotate the blade receiver 8 about the pivot 7, the pusher rod 15 is slidably mounted within the hollow elongated member and is pivotally connected to the blade receiver 8 at 16. The pusher rod 15 is pushed.

inwardly to place the curved cutting edge 3 of the blade 1 in position to be struck by the light rays A which will automatically be pushed outwardly by the spring 17 to rotate the blade receiver 8 back to its original position.

When a surgeons blade 1 having a curved and a straight cutting edge such as above described is tobe tested, the locator 12 is first raised to the position shown in the dotted lines in Fig. 3 and the blade 1 is placed between the clamping members 9 and 10 and held there by leaf spring 11. The blade is placed on the blade receiver 8 so that its point abuts the locator 12 which acts as a stop therefor, This insures that the blade 1 is properly located so that its curved cutting edge 3 has the pivot 7 for its center.

Thereafter, the locator 12 is lowered (Fig. 3) and the blade holder 1 is placed in the testing machine so that the light beams A strike the straight cutting edge 2 to determine its cutting ability.

Thereafter, the blade 1 is rotated on axis 7 by pushing the pusher rod 15 inwardly to rotate the blade receiver 8 on pivot 7. Since the pivot 8 is also the axis of the curved cutting edge 3 of blade 1, each portion of the cutting edge 3 will be placed on the same elevational plane as the straight cutting edge 2 so that the light beams A can scan the cutting edge 3 without a displacement in the light projecting apparatus. When the pusher 1 is released, the blade receiver 8 will return to its original position by means of the spring 17.

It will thus be seen, that the present invention provides a mechanism for determining the cutting ability of a blade which can index a blade edge having each section at a dilterent spatial level, which can maintain the cutting edge on the same plane as the straight cutting edge, and

in which the blade can be rotated to present a curved cutting edge of the blade on the same plane occupied by the straight cutting edge.

As various changes may be made in the form, construction and arrangement of the parts herein without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, 1 claim:

1. A blade holder for presenting to an apparatus which 4 by light scanning determines the cutting ability of a sharp edge of a blade, a blade having a cutting edge including a straight portion and a curved portion in which the curved portion is a simple curve with a single radius and a single center of curvature, said center being spaced transversely from the straight portion, in which the curved cutting portion is tangent to the straight portion, and in which the cutting edge is on the outside of the curved portion: said bladeholder comprising, a member having an elongated straight bottom and ,parallelelongated straight sides, a blade receiver on which the blade is adapted to be mounted, means situated at a fixed location on and carried by said member for supporting said blade receiver from said member for rotation about an axis perpendicular to the length of said member, said blade receiver including means for locating the blade on the blade receiver with the single center of curvature of the curved portion coincident with said axis of rotation, the blade receiver being rotatable between two positions in one of which the straight portion of the cutting edge is parallel to the length of the member and in the other of Which the straight portion of the cutting edge has been swung toward the bottom of the member, said blade receiver supporting means being located adjacent one end ofthe member, a manually manipulatable element adjacent the other end of the member, and a kinematic train'connecting said element and said blade receiver for rotating said blade receiver upon movement of said element.

2. A blade holder as set forth in claim 1 wherein the kinematic train constitutes a rod having one end flexibly connected to the blade receiver, the other end to the rod constituting the manually manipulatable element, the member including means for guiding the rod for longitudinal movement.

3. A blade holder as set forth in claim 1 wherein means is included to bias the blade holder toward the one position. 4. A blade holder for presenting to an apparatus which by light scanning determines the cutting ability of a sharp edge of a blade, a blade having a cutting edge including a straight portion and 'a portion of non-linear contour in which the nonlinear portion is tangent at one end thereof to the straight portion: said blade holder comprising, a member having an elongated straight bottom and parallel elongated straight sides, a blade receiver on which the blade is adapted to be mounted, means situated at a fixed location on and carried by said member for supporting said blade receiver from said member for movement relative to said member in a path congruent with the shape of said non-linear portion, the blade receiver being movable relative to the member between two positions, in one of which the straight portion of the cutting edge is parallel to the length of the member, said blade receiver supporting means being located adjacent one end of the member, a manually manipulatable element adjacent the other end of the member, and a kinematic train connecting said element and said blade receiver for rotating said blade receiver upon movement of said element.

References Cited in the file of this patent UNITED STATES PATENTS 1,876,314 Nickerson Sept. 6, 1932 1,955,129 Howe Apr. 17, 1934 2,027,595 Knobel et a1. Ian. 14, 1936 2,185,010 Young Dec. 26, 1939 2,264,676 Ostblad Dec. 2, 1942 2,421,358 Sneva May 27, 1947 2,491,346 Wetzel Dec. 13, 1949 2,521,291 Green Sept. 5, 1950 

